According to the present invention, the cooling apparatus is equipped with a thermostat for opening or closing a water passage between a radiator and a water-cooled engine and a cooling water passage switching valve for switching a water introducing passage for introducing the cooling water around a thermosensitive member of the thermostat. When the engine is in a high-load operating condition and when the temperature of the cooling water is equal to or higher than a predetermined temperature, the cooling water immediately after having flowed out of the water-cooled engine flows into around the thermosensitive member of the thermostat by the operation of the cooling water passage switching valve. As a result, the thermostat is operated in response to the temperature of the high temperature cooling water having flowed out of the water-cooled engine, and the set temperature of the cooling water by the thermostat can be shifted to a lower temperature. In this way, it is possible to prevent preferably an excessive rise in the temperature of the cooling water not only when the engine is in a high-load operating condition but also when the engine is in a state of hot soak such as in idling after the vehicle has travelled on an upward slope with a low speed.
A control to enable a further degree of enhancement in combustion efficiency in an automobile by effectively performing temperature control of cooling water in an automobile engine in accordance with various states of operation. Parameters from a variety of sensors that detect the state of an automobile engine are input into an engine control unit. Then, when the engine control unit determines from values of the accelerator opening and engine rotation speed, which serve as parameters indicating the operating state of the automobile, that the engine load is about to decrease, control is performed in the electronic control thermostat to maintain the cooling water temperature at a high temperature. Conversely, when it is determined that medium or high loads are due to increase, the control method is switched such that the electronic control thermostat is controlled by reading a target temperature corresponding to these parameter values from the engine control unit. Thus the electronic control thermostat variably sets the cooling water temperature in an engine cooling water temperature control system to a desired state in accordance with the engine load.
A system is provided wherein temperature conduction upon the changing of temperature of cooling water in an engine is forecast, and achievement of a cooling control system with an improved life and reliability and a reduction in cost results therefrom. A butterfly valve for regulating the flow of cooling water is rotatably controlled through a DC motor, a clutch mechanism 33 and a deceleration mechanism 33 so as to cool the engine at an appropriate temperature. A PWM signal generated by a quick response control and a PI control on the basis of at least load information of the engine is supplied to the DC motor 31 from ECU, whereby the butterfly valve 34b is rotatably controlled. A butterfly valve adjusting the flow of cooling water is controlled with the degree of valve opening by a thermo-element enclosing a thermal expansive body such as wax. A PTC heater is placed in proximity with the thermo-element, and supplied with current for heating on the basis of operation parameters of an engine to control the cooling efficiency of the cooling water. As a consequence, the characteristics of the butterfly valve which is capable of extremely decreasing rotation torque for adjusting the flow of the cooling water is used, so that mechanical stress can be reduced, resulting in improved life and reliability.
A valve for regulating fluid flow and associated method of use. The valve includes a stepper motor, a first valve chamber having an inlet port, a second valve chamber having an outlet port, wherein the first valve chamber includes an opening between the first valve chamber and the second valve chamber, a first member that is rotatable and operatively attached to the stepper motor, a second member that engages the first member for linear movement of the second member between a first position and a second position when the first member is rotated by the stepper motor, and a sealing mechanism that is operatively attached to the second member, wherein the sealing mechanism can move adjacent to the opening when the second member is in the first position and the sealing mechanism can move away from the opening when the second member is in the second position.
A valve for regulating fluid flow and associated method of use. The valve includes a stepper motor, a first valve portion having an inlet port for receiving fluid into the valve, a second valve portion having an outlet port for dispensing fluid from the valve, a third valve portion located between the first valve portion and the second valve portion, a first member that is rotatable and operatively attached to the stepper motor, and a second member, having a first portion and a second portion, which engages the first member for linear movement of the second member between a first position and a second position when the first member is rotated by the stepper motor to block fluid flow when the second member is located in the first position and allow fluid flow when the second member is located in the second position.
